Specifically, though not exclusively, the invention is applied in loading dies for for the formation of ceramic tiles in devices generally known as double-loading devices, usually structured so as to deposit internally of a forming cell of a die a layer of powder material, which is usually laid on top of an already-deposited layer of powder material.
These devices operate in combination with usual means for loading (drawers or trucks) a press, using various devices among which conveyor belts exhibiting an unloading frame which moves alternatingly horizontally above the cell in synchrony with the other means for loading.
The operation of these devices is proportionally better in relation to the overall width of the unloading frame (and therefore the belt conveyor), and also in relation to the rigidity and geometrical stability of the structure and the geometrical configuration of the unloading frame.
U.S. Pat. No. 3,294,218 discloses a carrier for supporting a portion of a belt comprising first roller means for supporting the midsection of said belt and second roller means for supporting the side sections of said belt. Each of second roller means have shaft means which have inner ends pivotally mounted on a support fixed to the frame of the carrier and outer ends supported by means that adjustably se cure said outer ends to respective upright posts fixed to the frame of the carrier for varying the angular position of the second roller means relative to the first roller means to change the cross sectional concave contour of the belt.
U.S. Pat. No. 3,259,227 discloses an idler assembly having an idler roll disposed on an inclined axis, a bracket for supporting one end of the idler roll, pivot means for pivotally mounting said bracket to permit the inclination of said idler roll axis to be varied, a second bracket like the first bracket for supporting the other end of the idler roll, and means adjustable upwardly and downwardly and pivotally connected to said second bracket to selectively adjust the position of said other end of th idler roil to thereby selectively set the inclination of the axis of said idler roll.
GB 1,494,960 discloses an adjustable support mechanism for conveyor mechanism including an endless load-carrying belt, the support mechanism providing inclined surfaces for supporting marginal edge portions of the load-carrying belt to cause the belt to trough and comprising a pair of support assemblies disposed in use one on each side of the conveyor, each support assembly including at least a pair of support brackets which are to be spaced apart longitudinally of the belt and capable of being secured adjustably to respective mounting brackets, each support assembly including also a carrier assembly and a plurality of rollers, each carrier assembly being pivotally adjustable on the support brackets, screwthreaded adjustment means being provided for adjusting the inclination of each carrier assembly on said support brackets for varying the degree of troughing of the belt.
The prior art all presents drawbacks with regard to the above qualities. For example, the width of the unloading frame is very limited. A further problem in the prior art is that it is difficult to maintain the right perfectly-centered and guided tension on the belt during movement above the underlying cell. This difficulty is manifested in the use of wide belts (2-3 meters and more) whose use is made practically impossible in known applications.
The main aim of the present invention is to obviate these limitations and drawbacks in the prior art.
An advantage of the invention is its simplicity.
A further advantage consists in its modular structure.
These aims and advantages and more besides are fully achieved by the present invention as it is characterised in the claims that follow.